Biochar for the removal of contaminants from soil and water: a review

Abstract

Biochar shows significant potential to serve as a globally applicable material to remediate water and soil owing to the extensive availability of feedstocks and conducive physio-chemical surface characteristics. This review aims to highlight biochar production technologies, characteristics of biochar, and the latest advancements in immobilizing and eliminating heavy metal ions and organic pollutants in soil and water. Pyrolysis temperature, heat transfer rate, residence time, and type of feedstock are critical influential parameters. Biochar’s efficacy in managing contaminants relies on the pore size distribution, surface groups, and ion-exchange capacity. The molecular composition and physical architecture of biochar may be crucial when practically applied to water and soil. In general, biochar produced at relatively high pyrolysis temperatures can effectively manage organic pollutants via increasing surface area, hydrophobicity and microporosity. Biochar generated at lower temperatures is deemed to be more suitable for removing polar organic and inorganic pollutants through oxygen-containing functional groups, precipitation and electrostatic attraction. This review also presents the existing obstacles and future research direction related to biochar-based materials in immobilizing organic contaminants and heavy metal ions in effluents and soil. Graphical Abstract

Data that support the use of agro-industrial residues from orange peel and sugarcane bagasse for the production of carbonaceous structures and their application in the removal of metal ions

“…Orange peel and sugarcane bagasse were used to obtain carbonaceous structures such as activated carbons and carbon foams for their application in the removal of heavy metal ions. The data set of this work shows information on the characterization and evaluation of these carbon materials that can be used as adsorbent materials, confirming recent reports [2] , [3] , [4] , [5] . Fig.…”

“…In general, pyrolysis showed higher ash content, higher surface area development due to the loss of carbon components at high temperatures, and higher micropore volume, respectively [4] . The chemical activation consisted in the surface modification using an acid treatment; this activation, increases the specific area and generates a variety of pores, it adds chemical groups such as oxygen and nitrogen [5] . Two activation temperatures were used during the production of AC, 500 °C and 700 °C, and phosphoric acid (H 3 PO 4 at 85 wt.%) was used as chemical reagent (Sigma Aldrich, 85% purity).…”

Recent Advances of Biochar-Based Electrochemical Sensors and Biosensors

“…The highly porous structure of biochar makes it ideal for use as an absorbent [ 14 , 16 ]. The detection of toxic heavy metals is always accompanied by a procedure of absorption.…”

“…The study of biochar on a large scale started in 2010 and moved to a reactivity exploration stage from 2014; the first works were reported in 1999 [ 6 ]. In order to better summarize the existing research results and to carry out more in-depth research on biochar, many review papers were published in the past decade [ 12 , 13 , 14 , 15 , 16 ]. Some comprehensive reviews identified biochar as a functional and novel material, in the context of a general discussion.…”

Efficient Nitrate Adsorption from Groundwater by Biochar-Supported Al-Substituted Goethite

“…Surface modification of biochar may improve its adsorption capability for nitrate by weakening the electrostatic repulsion between biochar and nitrate anions. Popular modification approaches consist of the protonation of negatively charged functional groups or loading of metal oxide/hydroxide particles on the biochar surface [26]. In particular, the supported iron oxide/hydroxide on biochar have been frequently reported due to their excellent properties, such as improved binding sites and point of zero charge [27].…”